The present invention relates to a constant current semiconductor circuit arrangement. More specifically, the invention relates to producing constant currents in the order of 10.sup.-12 to 10.sup.-3 ampere, whereby the accuracy shall be within the range of .+-.0.5%. Currents of this type are required in the field of nuclear physics and for the calibrating of rapid, automatic electrometer amplifiers. Known circuits of this type are, for instance, described in the book "Semiconductor Circuit Techniques" (Halbleiter-Schaltungstechnik) by U. Tietze and Ch. Schenck, publisher Springer-Verlag 1974, Pages 132 to 137. Such circuits comprise a field effect transistor as the operational transistor of the circuit. However, such circuits are not suitable for the intended purposes, especially where the production of currents in the Pico-Ampere range is involved. This is due to the transistor characteristics of the transistors employed heretofore in such comparable circuits.
Other known circuit arrangements for producing currents in the Pico-Ampere range require a costly network of high resistance resistors and field effect transistor switches. In addition, these prior art circuits have the disadvantage of relatively long transient or response times when the current values are changed. Constant current sources of this type are, for example, on the market under the name "Picoampere-Source", manufactured by Keithley Instruments, California.